Sinusitis is a condition affecting over 35 million Americans, and similarly large populations in the rest of the developed world. Sinusitis occurs when one or more of the four paired sinus cavities (i.e., maxillary, ethmoid, frontal, sphenoid) becomes obstructed. These paired cavities are located in the skull behind the face, as is depicted in FIGS. 1, 2, and 3A. Normally the sinus cavities, each of which are lined by mucosa, produce mucous which is then moved by beating cilia from the sinus cavity out to the nasal cavity and down the throat. The combined sinuses produce approximately one liter of mucous daily, so the effective transport of this mucous is important to sinus health.
Each sinus cavity has an opening into the nasal passage called an ostium. When the mucosa of one or more of the ostia or regions near the ostia become inflamed, the egress of mucous is interrupted, setting the stage for an infection of the sinus cavity, i.e., sinusitis. Infections of the maxillary and/or ethmoid sinuses make up the vast majority of cases of sinusitis, with far fewer cases involving the sphenoids and frontals.
Though many instances of sinusitis may be treatable with antibiotics, in some cases sinusitis persists for months, a condition called chronic sinusitis. Some patients are also prone to multiple episodes of sinusitis in a given period of time, a condition called recurrent sinusitis.
Currently, patients experiencing chronic sinusitis are eligible to have a surgical procedure called functional endoscopic sinus surgery (FESS). In this procedure, which almost always done in an operating room setting with the patient under general anesthesia, surgical cutting instruments are guided with an endoscopic visualization tool to the various sinus ostia and adjacent regions. Inflamed mucosa and underlying bony tissue are cut away in an effort to widen the outlet of the sinuses of interest. Once opened, the infected sinuses are able to drain and return to a relatively normal state.
While this procedure is generally effective, it is a relatively invasive procedure to the nasal cavity and sinuses. There can be significant post-operative pain for the patient, and sometimes there are bleeding complications that require packing to be placed in the nasal cavity. Subsequent removal of this packing can be quite painful. Also, since the nasal and sinus tissue are significantly traumatized, it may take several days to weeks to know whether the surgery was successful. This is especially true if various healing agents such as MeroGel® (Medtronic/Xomed) were placed at the surgical site, as these often block the sinus drainage until they are flushed away or degrade away after several days.
Additionally, in certain patients, the ostial regions of the surgically-treated sinuses can become re-obstructed with excess growth of scar tissue as a result of the tissue trauma. When the advantages and disadvantages of the surgery are considered for a patient with sinusitis, there are many patients in whom the surgery may not be appropriate. For example, their condition may not be considered “chronic enough” or extensive enough to warrant FESS surgery. In other situations, the patient may be fearful of the pain or other aspects of having FESS performed. Alternatively, the FESS procedure may be too costly for a particular patient.
For these and other reasons, there is a clear need for better methods and devices for the treatment of sinusitis.